Refactor web package and context package (#25298)

1. The "web" package shouldn't depends on "modules/context" package,
instead, let each "web context" register themselves to the "web"
package.
2. The old Init/Free doesn't make sense, so simplify it
* The ctx in "Init(ctx)" is never used, and shouldn't be used that way
* The "Free" is never called and shouldn't be called because the SSPI
instance is shared

---------

Co-authored-by: Giteabot <teabot@gitea.io>

services/auth/group.go

@@ -4,7 +4,6 @@
 package auth
 
 import (
-	"context"
 	"net/http"
 	"reflect"
 	"strings"
@@ -14,9 +13,7 @@ import (
 
 // Ensure the struct implements the interface.
 var (
-	_ Method        = &Group{}
-	_ Initializable = &Group{}
-	_ Freeable      = &Group{}
+	_ Method = &Group{}
 )
 
 // Group implements the Auth interface with serval Auth.
@@ -49,35 +46,6 @@ func (b *Group) Name() string {
 	return strings.Join(names, ",")
 }
 
-// Init does nothing as the Basic implementation does not need to allocate any resources
-func (b *Group) Init(ctx context.Context) error {
-	for _, method := range b.methods {
-		initializable, ok := method.(Initializable)
-		if !ok {
-			continue
-		}
-
-		if err := initializable.Init(ctx); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-// Free does nothing as the Basic implementation does not have to release any resources
-func (b *Group) Free() error {
-	for _, method := range b.methods {
-		freeable, ok := method.(Freeable)
-		if !ok {
-			continue
-		}
-		if err := freeable.Free(); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
 // Verify extracts and validates
 func (b *Group) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) (*user_model.User, error) {
 	// Try to sign in with each of the enabled plugins